This invention relates generally to the field of pressurized fluid systems and more particularly, but not by way of limitation, to a dual seat valve used to charge and evacuate a fluidic reservoir, such as a dome of a main valve to establish an overpressure path for a fluid.
Pressurized fluid systems are provided with pressure relief capabilities to prevent injury to personnel and damage to equipment in the event of an overpressure condition.
A commonly employed overpressure valve assembly, such as exemplified by U.S. Pat. No. 3,211,174 issued to Weise et al., generally comprises a normally closed main valve which is activated by an adjacent pilot valve. The main valve includes a piston assembly which is biased in a closed position against a valve seat by pressurized fluid supplied by the pilot valve. When an overpressure condition is reached, the pilot valve operates to reduce the pressure upon the piston, allowing the inlet fluid to advance the piston away from the valve seat and open the main valve.
While these and other prior art valve configurations have been found operable, there remains a continued need for improved configurations that are more precise, reliable and cost effective to manufacture and operate.
In accordance with preferred embodiments, a pilot valve is provided to charge and discharge a reservoir with fluid, such as a dome of a main valve in a pressure relief system.
The pilot valve includes housing which defines an interior chamber. An annular first seat surface is supported within the housing in communication with the interior chamber.
A valve assembly is configured for sliding movement within the housing, and includes a hollow stem with a distal end having an annular second seat surface. The second seat surface is extendable through a central orifice of the first seat surface.
A sealing member is disposed within the interior chamber to establish respective fluidic seals with the first and second seat surfaces. The sealing member preferably comprises a spherical ball, although other configurations can readily be used as desired.
During operation the pilot valve preferably moves between a first valve position and a second valve position. In the first valve position, the second seat surface extends through the first seat surface and abuttingly supports the sealing member to establish a fluidic seal between the sealing member and the second seat surface. This permits fluid to pass from the interior chamber into a gap between the sealing member and the first seat surface and on to charge the reservoir.
In the second valve position, the second seat surface is retracted away from the first seat surface so that the first seat surface abuttingly supports the sealing member to establish a fluidic seal between the sealing member and the first seat surface. This permits fluid to pass from the reservoir into a gap between the sealing member and the second seat surface to discharge the reservoir.
While preferred embodiments are generally directed to a pilot valve in an overpressure valve assembly, it is readily contemplated that the invention as disclosed and claimed is not so limited, but can be readily used in various other types of fluid delivery systems in various other fields.
These and various other features and advantages which characterize the claimed invention will be apparent from a reading of the following detailed description and a review of the associated drawings.